The present invention relates generally to multilayer optical materials and more particularly to multilayer magneto-optic photonic crystal materials tuned to produce an enhanced Faraday Rotation and transmission at particular wavelengths of visible radiation.
Faraday rotation, also called the Faraday Effect, is well-known in general, and its application to telecommunications systems using signals in the infrared spectrum is extensive. In brief, the Faraday Effect provides for changing a polarization angle of a radiation signal when a magnetic field is present in the direction of propagation. An amount of polarization angle change is a function of magnetic field strength, distance over which the magnetic field acts, and a Verdet constant of the material through which the radiation signal is propagating.
An advantage that telecommunications systems have is that they operate using infrared frequencies. At infrared frequencies, materials exist having good Verdet constants and good transmissivity constants. Material properties and structures affecting the Faraday Effect have been extensively explored for these applications.
Magneto-optic materials have been contemplated for use in magneto-optic displays. As well known, displays are generally of two types: monochromatic and multicolor. Obviously for a display, the radiation frequency(ies) are in the visible spectrum. It has been discovered that as the operating frequency of a magneto-optic display is decreased from the infrared spectrum into the visible spectrum, transmissivity of the radiation through materials having desirable effective Verdet constant values becomes unacceptable. Thus a multicolor display employing a red, green, and blue (RGB) primary color paradigm has yet to be realized for many reasons, one of which is the unavailability of suitable green and blue materials having sufficient Faraday rotation values and suitable transmissivity of the desired green and blue wavelengths.
What is needed are magneto-optic materials suitable for use in the green and blue spectrum.